Engine starter gearing



Jan. 18, 1944. D, P. KEARNEY ENGINE STARTER GEARING Filed Oct. 7, 1942 INVENTOR. lO/aruefi 1Q Patented Jan. 18, 1944 ITED. STATES. PATENT OFFICE V 2.33am

Daniel P. Kearney, Birmingham,

to Bendix.Aviation C Ind., a corporation of Mich, assignor rporation, South Bend,- Delaware Application 0mm '1, 1942, Serial No. 461,178 (c1. zoo-3s) Claims.

The present invention relates to engine starter gearing and more particularly to a drive of the type which automatically engages when the starting motorist energized and disengages when the engine starts.

' when drives of this type are used to crank engines which are subject to false starting, it is desirable to provide some means for maintaining the gear connection until the engine is reliably self-operative. Thus, many engines, particular-- ly when very cold, will fire in one or more cylinders enough to disengage the ordinary starter drive, and then fail to continue in operation. This necessitates a repetition of the entire cranking cycle of operation in order to re-engage the drive and resume cranking.

Various forms of drive have been developed for preventing de-mesh until a true start is secured, such for instance as disclosed in the pat cuts to Whitney, 2,004,643; Kearney, 2,218,972 and-'FitzGerald, 2,221,085. In each such true 5 parts in the positions assumed Fig. 2 is a cross section of the starter drive taken substantially on the line 2-2 of Fig. 1;

and

Fig. 3 is'a view similar to Fig. 2 showing the during the cranking operation.

In Fig. 1 or the drawing there is illustrated a starting circuit including a battery I grounded at 2 and connected by a lead 3 to a manually operable starting switch 4. Switch [is connected by a lead 5 to the starting motor SM which is grounded at 6 to complete the starting circuit.

starter drive some function of the engine or the starting motor is utilized to indicate a successful start and permit de-mesh of the drive. However, due to variations in operating characteristics'of engines and starting motors under the widely divergent conditions of use,'the optimum applicability of these devices is more or less specialized and no one type has been found best for all applications.

It is an object of the-present invention to pro-- vide a novel engine starter drive in which the engagement of the gearing is completely under the control of the operator.

It is another object to provide such a device in which the gearing is engaged by energization of the starting circuit, and is held in mesh as long as the starting circuit is energized.

It isv another object to provide such a device in which, when the starting circuit is de-energized, disconnection of the drive is brought about by the overrunning action of the'engine.

It isanother object to provide such a device incorporating'clutch means permitting the englue to overrunthe drive while the drive gear is maintained in mesh.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in

which:

Fig. 1 is a semi-diagrammatic illustration of a noid 2| mounted in The starting motor SM is arranged to actuate a shaft 1 which may be the extended shaft of the motor armature'and has fixed thereon in any suitable way a tubular shaft 8. A screw shaft 8 is slidably 'ournalled on the tubular shaft 8 and is yieldably connected to rotate therewith by means of a torsion spring connection H. A nut I2 is threaded on the screw shaft and is normally maintained in its idle position as illustrated by an anti-drift spring l3 which bears against a stop nut l4 fixed on the tubular shaft 8.

A barrel member I5 is rigidly attached at one end to the nut ii in any suitable manner as indicated at i6 and is provided at its other end with an overrunning clutch connection I! with a pinion l8 slidably journalled on the drive shaft 1 for movement into and out of engagement with a gear I9 01 an engine to be started.

Means for holding the pinion I! in mesh with the engine gear I! is provided in the form of a latch member 2| pivoted at 22 on the nut member 12 and having a shoulder 23 adapted to enter a notch 24 in the screw shaft under the action of a spring 25 when the nut has travelled on the screw shaft suiilciently to mesh the pinion with the engine gear.

Means under the control ot the operator for releasing the latch are provided in the form of a trip plunger 22 slidably mounted in a holder 21 threaded in the starting motor casing 20. The

free end 20 or the latch 2| extends radiallybe yond the body of the latch, and the plunger 22 is Means are provided for retracting the trip plunger "from the path of the latch 2| during energizationof the starting circuit. As here shown this is 'mr by means of a soleholder 21, connected by a lead 22 to the starting motor lead 5, and grounded at 23 so as to be energized from the battery i as long as the starting switch 8 is closed.

In operation, starting with the parts in the positions illustrated in Fig. 1, closure of the starting switch it by the operator actuates the starting motor SM and at the'same time energizes the shoulder 23 of the latch it carried by the control nut enters the notch 26 on the screw shaft under the action of the spring 25 as shown in Fig. 3. This engagement effectively prevents retrograde motion of the control nut on the screw shaft so as to positively hold the pinion in mesh with the engine gear.

When the longitudinal movement of the control nut is arrested by the stop'nut E6, the torque of the starting motor is transmitted to the pinion to crank the. engine in the usual manner. When the engine fires, the consequent acceleration of the engine gear i9 causes the pinion it to overrun the drive, such overrunning action be permitted by the clutch ll. De-meshing of the pinion, however, is prevented by the latch 26.

If the engine should fail to remain seli-opera= tive, as soon as it slow down to a speed corre= sponding to that of the starting motor the clutch it will re-engage and cranking will be resumed. When the engine becomes reliably seli operative, the operator opens the starting switch 6, thus lie-energizing both the starting motor and the solenoid 3i. Plunger 2B is then moved by the spring 29 into the path or the free end 8b of permitting the pinion to be ole-meshed by the control nut 52 overrunning the screw shaft a responsive jointly to the rotational effect trans mitted from the pinion it to the control nut, the deceleration of the screw shaft by the stoppage of the starting motor, and the longitudinal pressure of the anti-drift spring it. It will be readily appreciated thatthis arrangement pro vides means for positively holding, the pinion in 50 mesh irrespective of operating characteristics of the engine and starting motor as long as the starting switch is closed and for immediately causing tie-meshing of the drive when the starting switch is opened." puts the traversal of the pinion in complete control or the operator although the traversal is actually accom= plished in the ordinary manner by the threaded connection oi the drive.

aseaaae I Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are $08,

eible and that various changes may be made in 10 eluding a motor, a starter drive operated thereby including a pinion and means actuated by the motor to traverse the pinion into and out oi engagement with amember of an engine to be started, an overrunning clutch connection he tween the nut and pinion, means for positively 5 the design and arrangement of the parts withholding the pinion in engagement with the em gine member irrespective of the. rotative speed oi the pinion, and means responsive to de-energi-= nation or the starting circuit for releasing the holding means.

2. In an engine starting system a starting circuit including a motor, a pinion movable thereby to engage and rotate a-member of an engine to be started, means including a latch for positively holding the pinion in engagement with the engine member irrespective of the rotative speed of the pinion, means for tripping the latch and means responsive to energizatlon oi the start ing circuit for holding the tripping means out so of engagement with the latch.

3. In an engine starting system a starting'circult including a motor, a pinion movable thereby to engage and rotate a member of an engine to be started, an overrunning clutch connection be tween the motor and pinion, means including a 40 for holding the tripping means in inoperative latch 2i, thus tripping the latch and thereby" pinion into engagement with an engine gear and rotating the pinion to crank the engine, said means being operative to de-mesh the pinion responsive to overrunning or the engine gear, means for positively holding the pinion in mesh with the engine gear, means for releasing the holding means, and means responsive to energization of the starting circuit for preventing the operation of the releasing means.

/5. An engine starting system as set forth in claim 4 including further. an overrunning connection between the starting motor and pinion.

' DANIEL P. mam. 

